When you rename an object, you get a 301 redirect from the old URL to the new URL (good). However, if you rename the object back to the original name, this will cause a 301 redirect loop until the TTL on the 301 redirect clears.
1. Create an article /Test
2. Rename the article to /Test2. Check that /Test now redirects to /Test2
3. Rename the article back to /Test. Check that /Test redirects to /Test2, which redirects back to /Test. This loops.
The cause is that the 301 response does not have an X-Location-Id header in Varnish, thus when eZ Publish issues the ban request, the cache for that 301 redirect does not clear. This problem will go away when the TTL expires, so if you have a TTL of 120 seconds on 301 redirects, it will clear after 120 seconds. Of course, this is not acceptable on a live site – you want that 301 to clear right away.